In recent years, the wireless communication environment is confronting a problem of depletion of frequency resources, due to rapid increase of data traffic. Thus, there is a study of secondarily utilizing frequency channels. As one example, there is a study of secondarily utilizing what is called “television white space (TVWS)” with respect to television broadcasting. Also, as another example, there is a study for allowing a base station of small cell to utilize a frequency channel for a base station of macro cell in HetNet (Heterogeneous Network).
Several methods are conceived as a method in which a communication node, such as a master white space device (WSD) that secondarily utilizes a TVWS and a base station of small cell, utilizes a frequency channel. For example, as a first method, it is conceived to utilize a vacant channel that is not utilized. Also, as a second method, it is conceived to protect a main user of a primary system (for example, a television broadcast system), a base station of macro cell, and the like by some sort of means, and to utilize an adequate frequency channel in the entire frequency channels including the utilized frequency channel.
As one example of the above first method, for example, Patent Literature 1 discloses a technology in which the channel of TVWS is selected for each time period on the basis of channel vacancy information for each time period corresponding to position information, and wireless communication is performed on the basis of the selected channel of TVWS.